Drying apparatus and method for particle materials

ABSTRACT

Apparatus and a method for drying particle material with the use of hot gases wherein moist particle materials are moved through an open top conveyor tube as the gases move upwardly about the tube from a plenum therebelow and into a region above the tube to form a jet bed above the same for partially supporting the particle materials in a relatively dry condition. As the particle materials approach the downstream end of the conveyor tube they are projected upwardly and into the jet bed. Some of the relatively dry particle materials in the jet bed gravitate into the conveyor tube and a portion of the gases are deflected by the jet bed into the tube to assist in drying the relatively wet materials therein. The dry, fine particles are drawn out of the region by suction.

United States Patent [191 Graber 1 Mar. 26, 1974 DRYING APPARATUS AND METHOD FOR PARTICLE MATERIALS [76] inventor: David A. Graber, 315 Haight St.,

Menlo Park, Calif. 94025 [22] Filed: Feb. 28, 1973 [21] Appl. No.: 336,586

Primary Examiner-William F. ODea Assistant ExaminerWilliam C. Anderson Attorney, Agent, or Firm-Townsend and Townsend ABSTRACT Apparatus and a method for drying particle material with the use of hot gases wherein moist particle materials are moved through an open top conveyor tube as the gases move upwardly about the tube from a plenum therebelow and into a region above the tube to form a jet bed above the same for partially supporting the particle materials in a relatively dry condition. As the particle materials approach the downstream end of the'conveyor tube they are projected upwardly and into the jet bed. Some of the relatively dry particle materials in the jet bed gravitate into the conveyor tube and a portion of the gases are deflected by the jet bed into the tube to assist in drying the relatively wet materials therein. The dry, fine particles are drawn out of the region by suction.

10 Claims, 3 Drawing Figures DRYING APPARATUS AND METHOD FOR PARTICLE MATERIALS This invention relates to the drying of moist particle materials and, more particularly, to apparatus and a method for efficiently drying such materials with the use of hot gases without burning or scorching the materials.

BACKGROUND OF THE INVENTION SUMMARY OF THE INVENTION The present invention is directed to an improved dryer apparatus and method for particle materials wherein such material is more safely and efficiently dried than is capable with the use of conventional drying techniques. To this end, the invention utilizes a system wherein relatively moist particle materials are conveyed along a generally horizontal path as hot gases move upwardly on opposed sides of the path but out of direct contact with the particle materials flowing along the same. A relatively small portion of the gases enter the path so as to provide a drying action for the particle materials therein. The remainder of the gases define a jet bed above the path for supporting a slowly shifting mass of the particle materials after the materials have reached the downstream end of the path in a semi-dry condition and have been projected upwardly into the region above the path. Some of the particle materials in the jet bed fall back into the path and mix with the relatively wet particle materials therein to assist in drying the same. The conveyor urging the particle materials along the path acts as a hot air plenum and the particle materials are effectively dried without scorching or burning the same. The completely dried, fine particle materials can be drawn off in any suitable manner, such as by suction using a cyclone separator. The invention is suitable for use with a number of different typesof particle materials, such as oily or sugary materials and especially heat-sensitive materials.

The primary object of this invention is to provide an improved dryer apparatus and method wherein particle materials are effectively dried in a minimum of time with the use of hot gases without scorching or burning the materials.

Another object of this invention is to provide apparatus and a method of the type described wherein the relatively wet particle materials are conveyed along a generally horizontal path as hot gases pass upwardly about the sides of the path with a portion of the gases being deflected downwardly and into the path as the remainder of the gases define a jet bed for supporting partially dry particle .materials that have been projected upwardly from a downstream location of said path into the region thereabove, so that the particle materials can fall back into the path and assist in drying the relatively wet materials therein without scorching or burning the latter.

A further object of this invention is to provide an apparatus and method of the type described wherein the conveyor in the path along which the relatively wet materials are conveyed acts as a hot air plenum and the auger blade of the conveyor operates to prevent blowouts in the .jet bed thereabove to thereby assure effective drying of the particle materials and to allow the dried fine particles to be removed from the jet bed and collected at a remote location.

Other objects of this invention will become apparent as the following specification progresses, reference being had to the accompanying drawings for an illustration of the invention.

In the drawings:

FIG. 1 is a perspective view of the materials dryer of this invention, parts being broken away to illustrate details of construction;

FIG. 2 is a side elevational view of the apparatus; and

FIG. 3 is an enlarged, vertical cross section of the apparatus.

The materials drying apparatus of this invention is zones. Portion 14 is substantially cylindrical and is of I the same length as portion 12. A pair of end walls 20 and 22 close the ends of portions 12 and 14. A top 24 covers portion 12 and a stack 25 communicating with the interior of portion 12 extends upwardly and outwardly from top 24.

End wall 20 has a fluid inlet tube 28 extending therethrough and communicating with the interior of portion 14. Tube 28 is coupled to the outlet of a source of fluid under pressure, such as a blower 30. A fluid heating means 32, such as a gas burner, is disposed in tube 28 and is operable to heat the fluid flow therethrough so that the heated fluid will enter portion 14 and pass therefrom into portion 12 through the opening between zones 19 for a purpose to be described.

A generally horizontal materials delivery tube 33 is disposed within portion 14 and extends longitudinally thereof and partially into'the opening between zones 19 (FIG. 3). Tube 33 has a slot 34 at its upper'extremity, the slot being between zones with tube 33 being spaced inwardly of the zones to permit fluid flow from the interior of portion 14 upwardly and into the interior of portion 12 past the opposite sides of tube 33 as indicated by the arrows 35 and 36.

Tube 33 has a materials conveying auger 37 therein whose shaft 38 projects through end wall 20 and is coupled by a belt and pulley assembly 40 to the drive shaft 42 of a drive motor 44 secured in a fixed position relative to housing 11 in any suitable manner. Auger 37 operates to advance materials in tube 33 to the left when viewing FIG. 2 during the time in which motor 44 is energized.

Means for directing the materials into tube 33 includes a feeder 39 (FIG. 2) having a feed tube '41 in which a second auger 43 is disposed. Tube 41 is coupled by flange means 45 to the upstream end of tube 33 at a location outside portion 14. The upstream end of shaft 38 and the downstream end of shaft 47 of auger 43 are coupled to a common bearing (not shown) which can be connected to flange means 45 in any suitable manner, such as by a spider. Shaft 47 of auger 43 is coupled by a belt and pulley assembly 49 to the drive shaft 51 of a drive motor 53 secured by a bracket 55 to the outer surface of tube 41.

A feed hopper 46 carried by and communicating with tube 41 receives a flow 48 of materials to be dried from a delivery tube 50. Thus, auger 43 can deliver the materials to tube 33 when motor 53 is energized.

Portion 14 has a layer 61 (FIG. 3) of heat insulating material surrounding the same to prevent heat losses to the atmosphere. Also, a tube 63 containing a mass of heat insulating material therein surrounds the major portion of tube 33 to minimize heating thereof by gases flowing upwardly toward the opening between zones 19. Thus, materials in tube 33 will not be excessively heated and will be protected from being scorched or burned.

The downstream end of shaft 38 of conveyor 37 has a number of circumferentially spaced vanes 72 secured thereto within tube 33 to cause particle materials conveyed to the vanes to be projected upwardly through the downstream end of the opening between zones 19 and into portion 12 thereabove as shaft 38 continues to rotate under the influence of motor 44.

OPERATION Apparatus is placed in operation by directing wet particle materials into hopper 46 for gravitation into tube 34. Blower 30 and heater 32 are actuated so that air entering housing 14 will be heated. Thus, housing 14 acts as a hot air plenum and the hot air flow therein will pass upwardly and about tube 63, through passages 58 and 60 and into housing 12 thereabove. Arrows 74 indicate the upward flow of hot air into housing 12.

Motors 44 and 53 are actuated to cause movement of wet materials downstream of tubes 41 and 33 by rotation of augers 37 and 43. Thus, the relatively wet materials are conveyed toward vanes 72. The two rising hot air flows passing on opposite sides of slot 34 of tube 33 will tend to collide with each other because such flows are inclined as they pass through the passages adjacent to zones 19. This inclination is due to the cylindrical shapes of-lower portion 14 and tube 33. As a result, some of the hot air is directed downwardly and into tube 33 through slot 34. This portion of the .hot air operates to at least partially dry the relatively wet mate.- rials being conveyed in tube 33. As the partially dried materials reach vanes 72, they are projected upwardly and into upper portion 12. Eventually, sufficient material will be projected upwardly and form a jet bed 78 of relatively dry materials. The upward flows of hot air will partially buoy materials upwardly so as to sustain the configuration of the jet bed 78. Also, a portion of the relatively drymaterials in jet bed 78 will gravitate back downwardly and into tube 33 through slot 34 for mixture with the relatively wet materials therein so as to further facilitate the drying of these wet materials. Also, the jet bed, once formed, will operate to deflect portions of the rising air flows downwardly and into tube 33 as indicated by arrows 80.

As the drying process continues, relatively fine, dry particle materials are lifted and removed from housing assures that the drying process will continue without interruption.

Apparatus 10 can be used to dry different types of materials such as those having high moisture content,

oil materials, sugary materials, heat-sensitive materials and other types of materials. The drying method of the invention assures proper drying of the materials in tube 33 without scorching or burning the materials.

In the claims:

1. Drying apparatus for particle materials comprising: an elongated tube having a slot extending along the top thereof; means in the tube for conveying relatively wet particle materials along the same; means adjacent to one end thereof for directing a mass of particle materials into the tube; means adjacent to the tube for directing hot gases upwardly past the slot thereof along a pair of generally inclined paths on opposite sides of the tube with the paths being convergent as they extend upwardly; means above the tube and communicating with the slot thereof-for defining a closed region disposed for receiving a portion of the gases flowing along each path; and means adjacent to the opposite end of the tube for projecting particle material upwardly and into the region above the slot, the portions of the gases entering said region being sufficient to buoy up at least part of the materials projected thereinto to form a jet bed in said region adjacent to and above said slot.

2. Drying apparatus as set forth in claim 1, wherein said tube is transversely circular, said directing means including a housing surrounding said tube and spaced therefrom by a distance sufficient to present a pair of fluid passages on opposite sides of said slot.

3. Drying apparatus as set forth in claim 2, wherein is provided means coupled with said housing for directing a flow of air under pressure thereinto, said pressurized air, defining said gases, and means for heating the air flowing into said housing.

4. Apparatus as set forth in claim 1, wherein said projecting means comprises a number of vanes secured to said conveying means and responsive to the opertion of the latter.

5. Drying apparatus as set forth in claim 1, wherein said defining means comprises a housing above the tube, said housing having means for placing'a suction source in fluid communication with said region, whereby particle materials having a predetermined particle size can be drawn by suction out of said region.

6. Drying apparatus for particle materials comprising: a housing having an upper portion, a lower portion, and a slot-shaped opening placing said upper and lower portions in communication with each other; a tube in the housing adjacent to and extending longitudinally of the opening, said tube having a slot in the top portion thereof and being spaced from and in proximity to the junction between said upper and lower portions to define a pair of inclined fluid passages on opposite sides of the slot; actuatable means within the tube for conveying relatively'wet particle materials along the same; means coupled with said conveying means for actuating the same, means adjacent to one end of the tube for directing a mass of relatively wet particle materials thereinto for movement toward the opposite end thereof; means coupled with said lower portion for directing hot gases under pressure thereinto, whereby the gases will pass upwardly and through said passages with at least a portion of the gases being movable into said upper portion; and means in said tube adjacent to the opposite end thereof for projecting particle materials upwardly and into said upper portion as a function of the movement of the particle material through said tube, whereby the portion of the gases entering said upper portion will buoy up a part of the particle materials projected upwardly to thereby define a material jet bed above the tube.

7. Drying apparatus as set forth in claim 6, wherein said lower portion is provided with a cylindrical sidewall provided with said opening at the upper extremity thereof, said upper portion having a pair of spaced, in-

clined sides secured to said sidewall at the sides of the opening thereof, said sides being convergent as said lower portion is approached.

8. Drying apparatus as set forth in claim 6, wherein said upper portion is provided with a tubular stack adapted to be coupled to a source of suction, whereby relatively fine, dry particles can be drawn out of said upper portion by suction.

9. Drying apparatus as set forth in claim 6, wherein said tube has means on the outer surface thereof for insulating the same from the heat of the gases moving upwardly and about the tube.

10. Drying apparatus as set forth in claim 6, wherein said conveying means includes an auger in said tube, said auger having a central shaft, said projecting means including a number of circumferentially spaced vanes secured to the shaft at the downstream end thereof. 

1. Drying apparatus for particle materials comprising: an elongated tube having a slot extending along the top thereof; means in the tube for conveying relatively wet particle materials along the same; means adjacent to one end thereof for directing a mass of particle materials into the tube; means adjacent to the tube for directing hot gases upwardly past the slot thereof along a pair of generally inclined paths on opposite sides of the tube with the paths being convergent as they extend upwardly; means above the tube and communicating with the slot thereof for defining a closed region disposed for receiving a portion of the gases flowing along each path; and means adjacent to the opposite end of the tube for projecting particle material upwardly and into the region above the slot, the portions of the gases entering said region being sufficient to buoy up at least part of the materials projected thereinto to form a jet bed in said region adjacent to and above said slot.
 2. Drying apparatus as set forth in claim 1, wherein said tube is transversely circular, said directing means including a housing surrounding said tube and spaced therefrom by a distance sufficient to present a pair of fluid passages on opposite sides of said slot.
 3. Drying apparatus as set forth in claim 2, wherein is provided means coupled with said housing for directing a flow of air under pressure thereinto, said pressurized air defining said gases, and means for heating the air flowing into said housing.
 4. Apparatus as set forth in claim 1, wherein said projecting means comprises a number of vanes secured to said conveying means and responsive to the opertion of the latter.
 5. Drying apparatus as set forth in claim 1, wherein said defining means comprises a housing above the tube, said housing having means for placing a suction source in fluid communication with said region, whereby particle materials having a predetermined particle size can be drawn by suction out of said region.
 6. Drying apparatus for particle materials comprising: a housing having an upper portion, a lower portion, and a slot-shaped opening placing said upper and lower portions in communication with each other; a tube in the housing adjacent to and extending longitudinally of the opening, said tube having a slot in the top portion thereof and being spaced from and in proximity to the junction between said upper and lower portions to define a pair of inclined fluid passages on opposite sides of the slot; actuatable means within the tube for conveying relatively wet particle materials along the same; means coupled with said conveying means for actuating the same, means adjacent to one end of the tube for directing a mass of relatively wet particle materials thereinto for movement toward the opposite end thereof; means coupled with said lower portion for directing hot gases under pressure thereinto, whereby the gases will pass upwardly and through said passages with at least a portion of the gases being movable into said upper portion; and means in said tube adjacent to the opposite end thereof for projecting particle materials upwardly and into said upper portion as a function of the movement of the particle material through said tube, whereby the portion of the gases entering said upper portion will buoy up a part of the particle materials projected upwardly to thereby define a material jet bed above the tube.
 7. Drying apparatus as set forth in claim 6, wherein said lower portion is provided with a cylindrical sidewall provided with said opening at the upper extremity thereof, said upper portion having a pair of spaced, inclined sides secured to said sidewall at the sides of the opening thereof, said sides being convergent as said lower portion is approached.
 8. Drying apparatus as set forth in claim 6, wherein said upper portion is provided with a tubular stack adapted to be coupled to a source of suction, whereby relaTively fine, dry particles can be drawn out of said upper portion by suction.
 9. Drying apparatus as set forth in claim 6, wherein said tube has means on the outer surface thereof for insulating the same from the heat of the gases moving upwardly and about the tube.
 10. Drying apparatus as set forth in claim 6, wherein said conveying means includes an auger in said tube, said auger having a central shaft, said projecting means including a number of circumferentially spaced vanes secured to the shaft at the downstream end thereof. 